L-Tryptophan is an important amino acid that is marketed across America as a dietary supplement in the form of tablets, capsules, and powders. Although L-Tryptophan is legally defined as a dietary supplement by the Dietary Supplement Health and Education Act of 1994 (DSHEA), L-Tryptophan is primarily sold in the U.S. as a prescription drug. As a drug, L-Tryptophan is used to treat restlessness, insomnia, depression, and premenstrual syndrome (PMS) among other conditions. L-Tryptophan received widespread international attention in 1989 when tainted batches of L-Tryptophan dietary supplements caused Eosinophelia-Myalgia Syndrome (EMS) in a large number of people, ultimately leading to death in some cases.
Medical professionals related the syndrome to consumption of L-Tryptophan that was manufactured by using a bacterial fermentation process by Showa Denko K. K., Japan. Further investigation into the tainted batches revealed the contaminant to be trace chemicals identified as peak “X” on the monograph. The source of the contaminants was reported to have originated from specific strains of the bacterium Bacillus amyloliquefaciens used in the production process. Approximately 60 trace contaminants were identified in the tainted L-Tryptophan associated with the EMS outbreak. However, three compounds, namely, EBT (1,1′-Ethylidenebis L-tryptophan), Peak 200 (2,3-indolymethyl L-tryptophan), and Peak 1 (3-anilino-L-alanine) are considered as EMS-causing contaminants. All three of these compounds are collectively referred to as peak “X.”
L-Tryptophan continues to be commercially manufactured using bacterial fermentation; a process which may inadvertently result in trace chemical compounds, which are components of the collective EMS contaminant. Although effective purification methods are in place to separate and remove contaminants, the presence of potential EMS causing contaminants is not comprehensively documented or standardized.
In view of the above, there is a need and a demand for a standard method for the separation, identification, and quantification of contaminants in L-Tryptophan associated with EMS.
There is further need and demand for a method for the separation, identification, and quantification of EMS-associated contaminants in L-Tryptophan that is economical and/or straightforward to implement in a manufacturing setting.